[Potential role of ezrin and its related microRNA in ovarian cancer invasion and metastasis].

OBJECTIVE

to screen microRNA (miRNA) that inhibit expression of the metastasis-related gene ezrin in ovarian cancer cells and explore their correlation to the invasion and metastasis of ovarian cancer.

METHODS

the differential expression of ezrin in two paired high-metastatic and low-metastatic cell lines were examined by real time reverse transcription (RT)-PCR and western blot. A functional screen with microarray was employed to identify miRNA that were differentially expressed between SKOV3 and SKOV3ip cell lines. Three programs, TARGETSCAN (http://www.targetscan.org), MICROCOSM (http://www.ebi.ac.uk/enright-srv/microcosm/htdocs/targets/v5/) and PICTAR (http://www.pictar.mdc-berlin.de), were employed to identify all miRNA, which may inhibit the expression of ezrin and were differentially expressed between SKOV3 and SKOV3ip cells. To test the repressive potential of these miRNA, synthetic mimetics were transfected individually into SKOV3ip cells and endogenous ezrin expression levels monitored by western blot and real-time RT-PCR.

RESULTS

(1) the mRNA average level of ezrin were (81.74 ± 5.34)-fold higher expression level in SKOV3ip versus SKOV3 cells (P < 0.01), while (2.61 ± 0.14)-fold in HO-8910PM versus HO-8910 cells (P < 0.01). Elevated protein level of ezrin were observed in SKOV3ip cells compared with that in SKOV3 cells, and the same that in HO-8910PM cells compared with HO-8910 cells. Paired SKOV3 and SKOV3ip cells were employed to study the more significant difference in ezrin expression between them. (2) By a functional screen using miRNA microarray combined with bioinformatics analysis, the miR-183 and miR-22 were indentified as two candidate miRNA, which may have the potential regulatory role in ezrin expression. Real time RT-PCR assays revealed that miR-183 and miR-22 were, respectively, an average of (5.84 ± 0.66)-fold and (6.67 ± 0.67)-fold higher expression level in SKOV3ip versus SKOV3 cells (P < 0.01), which were in agreement with the microarray data. A subsequent validation by western blot and real time RT-PCR revealed that over-expression of miR-183 and miR-22 could both lead to an obvious decrease in ezrin protein level, while there were not signicant difference in the level of ezrin mRNA (P > 0.05).

CONCLUSION

increased expression of miR-183 and miR-22 may both repress the protein level of ezrin, indicating that miR-183 and miR-22 may bear a potential role in inhibiting ovarian cancer metastasis in a ezrin-mediated way.